In the field of injection molding for resin products, molds having multiple gates are used for multiple gate molding of single-cavity molded products with a large projected area or for so-called family molding, where a plurality of molded products that differ in resin filling amount and weight proportion are molded simultaneously, and with such a multiple gate arrangement, filling amounts from a plurality of nozzles must be adjusted to control and move locations of formation of weld lines of a molded product to desired positions and filling from the respective nozzles must be adjusted to enable sets of large and small molded products to be produced with stability.
For adjustment and control of filling amounts from a plurality of nozzles, for example, a filling amount of each nozzle is adjusted by changing an amount of resin injected from each nozzle gate as described in following Patent Documents D1 to D3.
D1: Japan Patent Prepublication No. 2004-50425
D2: Japan Patent Prepublication No. 2004-17564
D3: Japan Patent Prepublication No. H5-237879